What question did this study set out to answer?

The study aims to establish optimal definitions for ischemic core and penumbra in acute anterior DMVOs to enhance patient selection for EVT.

February 2, 2026

Abstract TP241: Redefining Ischemic Core, Penumbra, and Target Mismatch on CT Perfusion in Acute Anterior Distal Medium Vessel Occlusions

Key Points

The study aims to establish optimal definitions for ischemic core and penumbra in acute anterior DMVOs to enhance patient selection for EVT.
Retrospective analysis of patients with acute anterior DMVOs from four stroke centers.
Evaluated the correlation of various rCBF thresholds with MRI-based follow-up volumes to assess ischemic core.
Assessed how different Tmax thresholds correlated with follow-up volumes to evaluate penumbra.
Determined optimal target mismatch definitions based on the new core and penumbra metrics.
Increased correlation of FIVs with rCBF <38% for identifying ischemic core (CCC 0.30).
Tmax >8s showed a strong correlation with FIVs in penumbra assessment (CCC 0.49).
New TMM criteria improved identification of patients benefiting from EVT, showing significant risk reduction (absolute risk reduction 26%).

Abstract

Background: Recent trials of endovascular thrombectomy (EVT) for acute distal medium vessel occlusions (DMVOs) were negative but also used inconsistent imaging-based inclusion criteria, whereas many successful large vessel occlusion (LVO) EVT trials used empirically validated CT perfusion-based target mismatch (TMM) criteria: an ischemic penumbra (time-to-maximum Tmax >6s) to core (relative cerebral blood flow rCBF 4s, >6s, >8s, and >10s volumes correlated with FIVs in unrecanalized patients. Then, we evaluated whether these improved parameters for core and penumbra better quantified LVO TMM and identified an optimal DMVO TMM definition. Results: In 122 core patients, rCBF 8s most strongly correlated with FIVs (CCC 0.49 0.25-0.77), outperforming Tmax >6s (CCC 0.39 0.17-0.68) (p 6s to rCBF 8s and rCBF 8s to rCBF 8s best correspond to ischemic core and penumbra, respectively; more favorably quantify LVO TMM, and reveal optimal TMM criteria. These results should be prospectively investigated as inclusion criteria for EVT in this population and suggest recent negative DMVO EVT trials may have been confounded by suboptimal patient selection.

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